Thermal and Structural Modelling of Laboratory-Scale Pyrolysis Reactor

Abstract

This paper presents the steady-state thermal and static structural modelling of a laboratory-scale pyrolysis reactor for the thermal degradation of biomass wastes. A laboratory-scale pyrolysis reactor of volume 9.203 x 10-3m3 was developed to pyrolyse Palm Kernel Shell (PKS) and Palm Fruit Bunch (PFB) at varying temperatures of 350oC, 400oC, 450oC, 500oC, and 550oC. The reactor chamber was simulated for static-steady thermal and static structural analysis to determine the temperature distribution and thermal stresses induced in it. The model was developed using SolidWorks software, and a Computational Fluid Dynamics (CFD) simulation was carried out using ANSYS Workbench 19. A total number of 2,459 elements was generated composed of 8630 nodes using Hexahedra dominant meshing method. It was observed from the simulation result that the temperature distribution inside and outside the reactor chamber were 454.29oC and 550oC respectively. The maximum heat flux of 8.3466e+005 W/m² occurred at the inner chamber of the reactor due to the high concentration of the biomass waste and devolatization reaction, and the maximum equivalent (von-Mises) stresses the material can withstand at higher temperature is 1.6674e+009 Pa without rupture. It was found out from the simulation result that at a maximum temperature of 550oC, the equivalent (von Mises) stresses induced at the outer and inner chamber is 1.8585e+008 Pa, which is far lower than the maximum stress the material can withstand without rupture. Thus, the reactor is safe to operate at a temperature higher than 550oC without failure.